The present application relates to systems for deploying and/or retrieving intravascular stents, and more particularly relates to an apparatus for deploying and/or retrieving a self-expanding intravascular stent or medical device, including an intravascular stent delivery wire or pusher wire having one or more floating marker bands movably retained or constrained over the intravascular stent delivery wire or pusher wire for delivery and retrieval of an intravascular stent releasably placed over the one or more floating marker bands.
Intravascular stents are generally tubular and are actively or passively expanded radially in the vasculature of a patient. Such stents can be mounted over an expandable member or balloon of a balloon angioplasty catheter, for deployment of the stents by expansion of the balloon at the treatment site of the vasculature, such as at a stenosis or an aneurysm. Self-expanding stents can expand from a compressed delivery position to a larger diameter without the assistance of an expandable member or balloon.
Intravascular stent delivery systems for placement of an intravascular self-expanding stent at a treatment site in the vasculature typically have included a catheter that can be threaded through the vasculature with the self-expanding stent axially placed over a distal portion of the catheter. To position an intravascular stent at the treatment site of the vasculature, such as at a stenosis or an aneurysm, a guiding catheter is typically introduced into the vascular system of a patient, and advanced within the vasculature until the distal tip of the guiding catheter is adjacent to the treatment site. A guidewire is typically then advanced through the guiding catheter to the desired location, and then a dilatation or delivery catheter having a stent positioned on the dilatation or delivery catheter is advanced into the patient's vasculature over the guidewire, until the stent is properly positioned, after which the stent can be deployed at the treatment site.
One common technique for maintaining a self-expanding stent in a low profile configuration involves placement of a sheath or a sleeve over some or all of the stent, typically either to retain the stent in a compressed configuration around the catheter, to prevent body fluids from reaching the stent, or to protect the vasculature from the stent. Usually such a sheath or sleeve is retracted or released from the stent to allow the stent to achieve an expanded configuration.
A guidewire loaded stent is also known in which a radially expandable stent carried on a guidewire is covered in part by a retractable restraining sheath at or near a distal end of the guidewire. When the stent is placed at a treatment site, the restraining sheath is retracted to expose the stent and thus allow the stent to expand.
It would be desirable to provide an intravascular stent delivery system, including an intravascular stent delivery wire or pusher wire having one or more floating marker bands movably retained or constrained over the intravascular stent delivery wire or pusher wire for delivery and retrieval of a self-expanding intravascular stent or medical device releasably placed over the one or more floating marker bands, in order to provide a reduced diameter profile to permit delivery of an intravascular stent to smaller diameter and more delicate vessels of the vasculature, such as the neurovasculature.
It would also be desirable to provide an intravascular stent delivery wire or pusher wire having one or more floating marker bands movably retained or constrained over the intravascular stent delivery wire or pusher wire to allow for an integration of a proximal or distal segment of a self-expanding intravascular stent or medical device with the intravascular stent delivery wire or pusher wire to be fit into a catheter or tubular sheath and advanced and retracted within the catheter, within the vasculature of a patient, and to allow for the self-expanding intravascular stent or medical device to be retrieved back into the catheter after partial stent deployment.
It would also be desirable to provide an intravascular stent delivery wire or pusher wire having one or more floating marker bands movably retained or constrained over the intravascular stent delivery wire or pusher wire with a self-adjusting, variable gap between the self-expanding intravascular stent or medical device and a fixed marker band fixedly mounted on the intravascular stent delivery wire or pusher wire, in order to facilitate ease of advancement or retraction of the assembly and to allow for improved articulation of the self-expanding intravascular stent or medical device with respect to the intravascular stent delivery wire or pusher wire in a narrow vascular curvature which would otherwise not allow for traversing of the curve with conventional systems.
It also would be desirable to provide an intravascular stent delivery system including an intravascular stent delivery wire or pusher wire having one or more floating marker bands movably retained or constrained over the intravascular stent delivery wire or pusher wire for delivery and retrieval of an intravascular stent releasably placed over the one or more floating marker bands, so that the intravascular stent delivery wire or pusher wire tip is free to rotate during system advancement, for ease of navigating tortuous vascular anatomy.
It also would be desirable to provide an intravascular stent delivery system including an intravascular stent delivery wire or pusher wire with one or more floating marker bands having an outside circumference with a multi-sided or polygon shape, such as a square shape or pentagonal shape, for example, to allow for struts, legs or radiopaque markers of the self-expanding intravascular stent or medical device to extend beyond the one or more floating marker bands so that the struts, legs or radiopaque markers of the self-expanding intravascular stent or medical device are constrained by the catheter or tube wall and by one or more sides of the one or more floating marker bands, to allow for the self-expanding intravascular stent or medical device to interface with the intravascular stent delivery wire or pusher wire, and to allow the self-expanding intravascular stent or medical device to maintain column strength not to buckle under compression loads, particularly so that the self-expanding intravascular stent or medical device can be retrieved under tensile loads.
It also would be desirable to provide an intravascular stent delivery system including an intravascular stent delivery wire or pusher wire with one or more floating marker bands that can be located under the body of the self-expanding intravascular stent or medical device to provide support for the self-expanding intravascular stent or medical device, and to prevent or minimize stent buckling of the self-expanding intravascular stent or medical device. The present invention meets these and other needs.